---
title:  Host Machine Requirements
---

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Host machines must meet a set of requirements for Apache Geode.

<a id="system_requirements__section_1E1F206FBC8B4A898A449E0699907A7A"></a>
Each machine that will run Apache Geode must meet the following requirements:

-   Java SE Development Kit 8 or a more recent version.
-   A system clock set to the correct time and a time synchronization service such as Network Time Protocol (NTP). Correct time stamps permit the following activities:
    -   Logs that are useful for troubleshooting. Synchronized time stamps ensure that log messages from different hosts can be merged to reproduce an accurate chronological history of a distributed run.
    -   Aggregate product-level and application-level time statistics. 
    -   Accurate monitoring of the Geode system with scripts and other tools that read the system statistics and log files.
-   The host name and host files are properly configured for the machine. The host name and host file configuration can affect `gfsh` and Pulse functionality.
-   Many default Linux installations use SYN cookies to protect the 
system against malicious attacks that flood TCP SYN packets.
The use of SYN cookies dramatically reduces network bandwidth,
and can be triggered by a running GemFire distributed system.

    To disable SYN cookies permanently:
    1. Edit the `/etc/sysctl.conf` file to include the following line:

        ``` pre
        net.ipv4.tcp_syncookies = 0
        ```
        Setting this value to zero disables SYN cookies.
    2. Reload `sysctl.conf`:

        ``` pre
        sysctl -p
        ```
